Biomedical subjects

E N Martínez

Publications and source records attributed to E N Martínez.

3 recordsLinked to original sources

PubMed2000

Second-line treatment with gemcitabine and vinorelbine in non-small-cell lung cancer (NSCLC) cisplatin failures: a pilot study.

PURPOSE: This pilot study was designed to evaluate the efficacy and toxicity of the gemcitabine/vinorelbine combination in non-small-cell lung cancer (NSCLC) patients who had failed cisplatin-based first-line chemotherapy. PATIENTS AND METHODS: Eligible patients had refractory or resistant NSCLC, WHO performance status 0-2, adequate hematologic parameters and normal hepatic, renal and cardiac function. Gemcitabine (1200 mg/m2) was administered on days 1, 8 and 15; vinorelbine (25 mg/m2) was administered on days 1 and 8, every 4 weeks until patients experienced disease progression. RESULTS: From September 1997 to March 1998, 16 patients were enrolled (six: stage IIIB: ten: stage IV). All 16 patients were assessable for toxicity and evaluated for response. One complete (6.25%) response and no partial responses were observed. Median survival was 25 weeks (95% CI 19-30). A median of 3.31 courses per patient was administered, and the median interval between courses was 28 days. The median delivered dose was 664.85 mg/m2 per week of gemcitabine and 10.71 mg/m2 per week of vinorelbine, corresponding to a relative dose intensity of 0.73 and 0.85, respectively. Grade 2/3 thrombocytopenia occurred in 13 (24.52%) of 53 courses administered. Neutropenia Grade 2/3 occurred in 14 courses (26.41%). There were seven (13.20%) episodes of fever related to the drug administration. Mild asthenia was observed in six (37.5%) patients. Other toxicities were mild to moderate. CONCLUSION: These results suggest that this gemcitabine/vinorelbine combination is not an active salvage regimen in patients with refractory NSCLC. The combination merits further evaluation with modified regimens.

Adult↗

PubMed2000

Amaranth globulin structure modifications induced by enzymatic proteolysis.

Globulin-P was partially hydrolyzed with papain under specific conditions to study the resulting structural modifications. Under mild hydrolytic conditions, globulin-P polymers were cleaved to render their unitary constituents (280 kDa molecules). Under stronger hydrolytic conditions these unitary molecules were 13% smaller than those from nonhydrolyzed globulin. Moreover, these molecules remained assembled even though they contained degraded polypeptides. The monomeric (M) subunit and the A chains were preferentially cleaved under mild and intermediate hydrolytic conditions, whereas B chains remained with the same size. These results suggest that the M and A polypeptides might be located at an exposed site of the molecules resembling the structure of the legumins. The M subunit may be participating in the stabilization of globulin-P polymers, on the basis that these two species disappeared under the same hydrolytic conditions. Similar events such as those described in this paper might be taking place on globulin-P during germination of amaranth grain.

Edible Grain↗

PubMed1999

Role of disulfide bonds upon the structural stability of an amaranth globulin.

Analysis of globulin-P, the polymerized amaranth globulin, gave a low amount of free sulfhydryls (10.2 +/- 0.5 micromol/g) from which 7 +/- 1 micromol/g was buried inside the molecule. In addition, its disulfide content was high (51 +/- 1 micromol/g) and similar to soybean 11S globulin content. The more exposed disulfide bridges were found to be stabilizing polymers, whereas the less reactive bridges were either linking P(20) and P(30) polypeptides or forming intrachain linkages. It was found that the buried bonds participate in the stabilization of folded polypeptides and the quaternary structure of the globulin. In turn, the dissociation of polymers and disruption of the quaternary structure by the action of 2-mercaptoethanol reverted upon removal of the reducing agent. This demonstrates that the polymerized state and the quaternary structure of the molecules are most favorable from the thermodynamic point of view. The similar content of SH and SS in globulin-P and globulin-S found in this laboratory suggests that the differences between these proteins may be ascribed to other compositional differences.

Calorimetry↗